Minelab GPX-4500 User manual

Brand: Minelab

Model: GPX-4500

Category: Measuring, testing & control

Type: User manual

Instruction Manual

Quick Start

Set the front panel switches to the following positions:

Threshold

Auto Tune

Ground

Balance

Tracking

Fixed

Threshold

On/Off

Hold for FP

Push and release the On/Off switch on the rear

control panel (pg. 25).

Turn the Threshold (pg. 34) control clockwise until a hum

is audible through the headphones.

Raise the coil off the ground and Press the Auto Tune

(pg. 33) button to reduce electrical interference. The

tuning process takes approximately 60 seconds. Do not

move the coil or pass metal objects near the coil during

the tuning process.

Whilst lowering and raising the coil between 25mm and

100mm (1" and 4") from the ground, change the Ground

Balance switch to Tracking (pg. 40). Any variations in the

Threshold will smooth out within 3–5 seconds.

Adjust the Threshold (pg. 34) to a very faint but still

audible level. It should be smooth with only minor

fluctuations.

You are now ready to start searching!

Mode

Soil /

Timings

Ground

Balance

Coil /

CancelTrackingSpecialDeep

Custom Enhance Fixed Double D

MNG

Item Number: 4901 - 0063

Revision: 1.1

THIS DEVICE COMPLIES WITH

PART 15 OF THE FCC RULES

Operation is subject to the following two

conditions: (1) this device may not cause

harmful interference, and (2) this device

must accept any interference received,

including interference that may cause

undesired operation.

Disclaimer:

The Minelab metal detector discussed

in this operating manual has been

expressly designed and manufactured as

a quality hobbyist metal detector and is

recommended for use in coin, treasure and

general metal detection in non-hazardous

environments. This metal detector has not

been designed for use as a mine detector

or as a live munitions detection tool.

Working for a Cleaner,

Greener Future

For Consumers within the European

Union: Do not dispose of this equipment

in general household waste.

The crossed wheeled bin symbol on this

equipment indicates this unit should

not be disposed of in general household

waste, but recycled in compliance

with local government regulations and

environmental requirements.

Please dispose of this equipment via a

recycling service or centre, or by returning

the unit to the respective Minelab outlet

as appropriate for your unit. This will enable

the equipment to be disposed of in an

environmentally safe manner.

Disposal of unwanted electronic

equipment in land ﬁlled waste may

contribute to adverse long term

environmental eﬀect due to the

leaching of contaminating and toxic

substances contained within some

electronic equipment.

Minelab Electronics Pty Ltd

This document contains proprietary

information which is protected by

permitted under the Copyright Act

1968, no part may be reproduced by

any process without written permission

from Minelab Electronics Pty Ltd, 118

Hayward Avenue, Torrensville, SA 5031,

Australia.

WARNING. This document contains

Minelab Electronics Pty Ltd rights,

technical data or restricted rights data,

or both. Patents and trademarks apply.

The World Leader in Metal Sensing Technology

From our origins in 1985, Minelab have specialised in advanced electronic

technologies. Our competitive advantage was created almost immediately with a

highly competent and innovative Research and Development team, inspired by the

genius of Mr Bruce Candy.

This commitment to innovation has enabled us to successfully market feature

packed Consumer coin and treasure detectors enjoyed by hobbyists worldwide

as well as high quality gold detectors used by both professionals and amateurs.

Minelab’s advanced technology is also incorporated in detection equipment

designed for military and humanitarian de-mining projects throughout the world.

Today Minelab has manufacturing, distribution and customer service operations

in Australia, Europe and the United States, and is an ISO 9001 Quality Endorsed

Company. ISO 9001 is a worldwide quality standard certification that ensures the

highest level of product quality for our customers.

Please note:

Since there may be a variety of options

available for this detector, equipment

may vary according to the Model or

items ordered with your detector. Certain

descriptions and illustrations may also

diﬀer (in this manual) from the exact Model

that you purchased. In addition, Minelab

reserves the right to respond to ongoing

technical progress by introducing changes

in design, equipment and technical

features at any time.

Minelab Electronics Pty Ltd

PO Box 537, Torrensville Plaza

Adelaide, South Australia, 5031

Australia

Tel: +61 (0) 8 8238 0888

Fax: +61 (0) 8 8238 0890

Email: [email protected]

Minelab International Ltd

Laragh, Bandon

Co. Cork

Ireland

Tel: +353 (0) 23 52101

Fax: +353 (0) 23 52106

Email: [email protected]

Minelab USA Inc

871 Grier Drive, Suite B1

Las Vegas, Nevada, 89119

USA

Tel: +1 702 891 8809

Fax: +1 702 891 8810

Email: [email protected]

For further product information

and detecting tips, refer to:

WWW.MINELAB.COM

Minelab is always interested in your opinions. If you have

any questions or comments regarding the GPX-4500 or any

other Minelab product, please feel free to contact us via

your local Authorised Minelab dealer, or write to us:

Gold detecting is a fascinating and rewarding

activity enjoyed by people all over the world. By

getting to know your GPX-4500 you can become one

of the many who find gold and valuable treasure.

The GPX-4500 is Minelab's most advanced

gold detector. It is a high precision instrument

incorporating Multi-Period Sensing (MPS), Dual

Voltage Technology (DVT), Smart Electronic Timing

Alignment (SETA), and the latest in high-tech

analogue components combined with advanced

digital processing.

The GPX-4500 will locate gold in all types of ground,

especially highly mineralised ground conditions,

with greater efficiency than any previous detector.

This manual is designed to help both the beginner

and expert prospector get the best performance out

of the GPX-4500.

Minelab wishes you every success in your quest

for gold and treasure!

Congratulations on

Purchasing the Minelab

GPX-4500

Contents

Quick Start Back Cover

Introducing the GPX-4500 4

List of Parts 6

Assembly 8

Adjusting the Detector for Comfortable Detecting 16

Charging the Battery 18

Battery LED Patterns 20

Taking Care of Your Battery 21

Detecting Basics 22

Detector Sounds 23

Front Control Panel 24

Rear Control Panel 25

Turning the Detector On 26

LCD Menu Structure 27

Search Mode 28

Tune / Reducing Electrical Interference 32

Auto Tune 33

Threshold / Adjusting the Background Audio Level 34

Soil/Timings / Optimising for Soil & Target Types 36

Ground Balance / Reducing Ground Noise 38

Ground Balance Procedure for Tracking 40

Ground Balance Procedure for Fixed 42

Coil/Rx / Changing Transmit and Receive (Rx) Fields 44

Resetting Factory Presets 46

Factory Presets 48

Function Select 50

Setting 51

Accessing Functions 52

Accessing Settings 53

LCD Backlight 54

Battery / Viewing the Battery Voltage 55

Volume Limit / Setting the Max Volume of all Sounds 56

Ground Balance Type 58

Ground Balance Procedure for Specific 60

Special / Soil/Timings 61

Manual Tune / Reducing Electrical Interference 63

Changing Search Modes 64

Motion / Adjusting Sweep Speed 66

Rx Gain / Adjusting the Sensitivity of the Detector 67

Audio Type / Changing the Response of Target Signals 68

Audio Tone / Adjusting the Pitch of the Threshold 69

Stabilizer / Controlling the Stability of the Threshold 70

Signal Peak / Adjusting Pitch Variation of Target Signals 72

Target Volume 73

Response / Inverting the Pitch of the Target Signal 74

Tracking Speed / Keeping up with Changing Ground 76

Iron Reject 78

Iron Reject / Rejecting Ferrous Targets 80

Custom Name 82

Pinpointing / Locating the Target 84

Recovering the Target 86

Detecting Tips 88

Commander Coils 90

Choosing the Right Coil for the Job 92

Troubleshooting 94

Glossary of Terms 95

Taking Care of Your Detector 98

Technical Specifications 99

User Preferences 100

User Notes 102

Warranty 103

Service Repair Form 104

Function

Select

Setting

On/Off

Hold for FP

Auto Tune

Mode

Soil /

Timings

Ground

Balance

Coil /

CancelTrackingSpecialDeep

Custom Enhance Fixed Double D

MNG

Threshold

Coil

Smart

Point

Item Number: 4901 - 0063

Revision: 1.1

Introducing

the GPX-4500

Rx Gain

The Rx Gain function sets the overall

sensitivity level of your detector. In

areas where soil conditions are mild

you can increase the Rx Gain. In areas

that are more difficult Rx Gain can

be reduced.

Timings

The GPX-4500 features a number of

new timings, increasing performance in

different conditions.

Ground Balance (GB) Type

Ground Balance Type now has three

settings: Normal, Specific, and GB Off.

Normal is the preferred setting for most

soil types. Specific Ground Balance

is designed to be used in very hot

ground, and is especially useful with

Monoloop coils. GB Off switches the

ground balance circuit off for maximum

depth in very mild soils, sand etc.

Response

The Response function allows you

to invert the target response. Deep

targets can now sound like the more

familiar 'rising and falling' pitch of a

shallow target signal.

The GPX-4500 utilises Minelab’s proven 'Dual Voltage

Technology' (DVT). This ensures an accurate Ground

Balance to provide maximum sensitivity and depth

in all ground types.

The GPX-4500 offers a total of six Timing options,

each incorporating the all-new SETA technology.

Smart Electronic Timing Alignment (SETA) ensures

the detector is precisely aligned for each individual

Timing option. This improvement in calibration

reduces the susceptibility to certain types of

interference, and significantly improves

the detector’s immunity to highly magnetic

rocks and soils.

Through a process of dynamic noise compensation,

SETA ensures that the threshold stability is improved

and maintained, allowing you to operate the GPX-

4500 with maximum efficiency under all conditions.

The GPX-4500 now offers six preprogrammed

Search Modes, set up for the most common

search techniques.

All modes can be fine tuned by simply scrolling

through the various functions of the detector and

adjusting the settings.

With improved fuctionality and new timings the

GPX-4500 is capable of finding nuggets in a diverse

range of ground conditions with greater ease than

previous detectors.

Motion

The speed at which you sweep the

coil has an effect on target response

time and Ground Balance adjustment.

Matching your preferred coil sweep

speed with the corresponding Motion

setting can reduce noise and improve

your ability to pick up targets at depth.

Custom Search Mode

With Custom selected, a range of new

custom search mode positions become

available from the LCD menu. A new

mode name picker is also included.

Create your own modes for different

locations and use them for future visits.

Stabilizer

This is a new feature which allows you

to fine tune your audio, to obtain the

best compromise between smooth

operation and clear target signals.

Target Volume

Used to control the built-in amplifier

which affects the volume of target

signals. It is active with both

headphones and an external speaker.

Target Volume can also be used to

reduce the severity of ground signals.

Functions

Overview

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List of Parts

Attaching the Coil to the Lower Shaft:

1 Plug the two rubber washers into the holes on

either side of the lower shaft.

2 Ensure that the spring loaded pin of the lower

shaft is pointing downwards. Slide the lower shaft

into the bracket on top of the coil.

3 Insert the bolt through the lower shaft and the

bracket on top of the coil. Fasten with the nut

provided; being careful not to damage the thread

of the nut by over-tightening. This may need to

be loosened to adjust the coil to a comfortable

detecting angle.

Note: If the coil becomes loose over time the rubber

washers may need replacing.

Assembly

Attaching the Lower Shaft to the Upper Shaft:

1 Rotate the twistlock of the upper shaft counter-

clockwise to ensure it is loosened.

2 Compress the spring loaded pin of the lower shaft.

Slide the lower shaft into the upper shaft until the pin

reaches an adjustment hole. The pin will spring out

and clip into place.

3 Rotate the twistlock clockwise to clamp the lower

shaft and prevent movement.

Attaching the Handle to the Upper Shaft:

1 Slide the bungy cord clamp onto the upper shaft.

2 Slide the handle onto the upper shaft so it slopes

away from you, as seen below.

Attaching the Armrest to the Upper Shaft:

1 Place the two armrest halves on either side of

the upper shaft, aligning the armrest and upper

shaft holes.

2 Insert the bolts through the armrest and upper

shaft holes.

3 Loosely fasten the wing-nuts onto the bolts (these

will be tightened after the control box is attached).

spring loaded pin

The Coil cable is directly wired into the coil and

is not removable. Any attempt to disconnect

this cable will void your warranty

Assembly

Connecting the Coil Cable:

1 Wind the coil cable around the lower and upper

shafts enough times to take up the slack. Leave

enough slack at the bottom of the cable near the

coil to allow the angle of the coil to be adjusted

while detecting.

2 Use the velcro straps to secure the coil cable to

the shaft.

3 Plug the coil connector into the coil socket on the

control box, firmly tightening the retaining ring to

hold it in place.

Attaching the Armrest Strap to the Armrest:

1 Press both strap studs onto the armrest studs.

2 Push the armrest straps through the slots in

the armrest cover and then slide the cover

over the armrest.

Connecting the Control Box to the Upper Shaft:

1 Place the detector on a flat surface, with the

handle facing upwards.

2 Position the armrest on top of the control box.

3 Clip the control box onto the armrest, ensuring

the battery plug faces away from the coil.

4 Fasten with the wing-nuts.

5 Wind the Quick-Trak button cable around the

upper shaft and plug it into the Smart Point

socket in the control box. Ensure that the cable is

wrapped firmly but avoid strain on the connector.

Always ensure that the control box is turned

off before connecting or disconnecting the coil

to avoid damage to the detector's electronics.

Note: If the Quick-Trak

cable becomes loose try

securing it onto the shaft

with electrical tape.

Connecting the Battery Pack:

1 Place the battery into the battery harness pouch.

2 Connect the headphones and the power cable to

the appropriate sockets in the battery.

Assembly

Note: The illustration shows

the battery orientated for

a user holding the detector

with their left hand.

Making use of the GPX-4500 Amplifier:

In previous Minelab detectors if a speaker was used,

instead of headphones, the audio level would be

significantly reduced. Now, the new Minelab Lithium

Ion battery contains an additional amplifier which

automatically increases the audio level when a

correctly wired speaker is used.

The new Minelab Lithium Ion battery will

automatically detect if headphones or a speaker is in

use and adjust the audio level accordingly.

See wiring diagram below for correct speaker to

audio jack wiring.

Note: After market

accessory boosters may

not operate in conjunction

with this built in amplifier.

However, the detectors

'Target Volume' adjustment

allows you to adjust the

target signal volume and

threshold, so accessory

boosters are unlikely to

be needed.

Caution: Never re-wire your headphones so that

they are similar to the external speaker as the

audio level may damage your hearing.

External Speaker

TipRing

Caution: The battery should initially be charged

for 8 hours before use.

Not connected

Assembly

Fitting the Battery Harness:

1 Thread your arms through the harness,

so the battery pack sits on your back.

2 Clip the waist and chest buckles together.

For more detail see Adjusting the Detector

for Comfortable Detecting (pg. 16).

Attaching the Bungy Cord:

1 Create a loop in the bungy cord.

2 Undo the plastic wingnut and remove the

bolt from the clamp.

3 Push the bolt back through the clamp and

loop to secure the bungy cord to the shaft.

4 Fasten the screw with the wingnut.

5 Clip the bungy cord onto one of the harness

shoulder strap rings.

For more detail see Adjusting the Detector

for Comfortable Detecting (pg. 16).

Note: For comfortable,

long term detecting, it is

important you take the

time to adjust the

detector correctly.

Adjusting the Detector

for Comfortable Detecting

Adjusting the Battery Harness:

A comfortable fitting battery harness will ensure the

longest detecting session possible without fatigue.

Ideally the battery should be placed on your back so

that it counter-balances the weight of the detector.

You should be able to reach the switches of the

detector without putting excess strain on the

bungy cord.

Pull the straps outwards and downwards to tighten.

Push the straps back through the buckle to loosen.

The harness may also be adjusted around your body

by threading the front straps through different loops

on the waistbelt.

Adjusting the Bungy Cord Clamp

(Bow Knuckle):

The correct position of the bungy cord clamp (bow

knuckle) along the shaft can help take the weight of

the coil.

Loosen the clamp screw so it can slide along

the shaft. Slide it to a position that feels most

comfortable for you.

Note: You may need to change the length of the bungy

cord, or the position of the bungy cord clamp, when

you change coils or detect on sloping ground.

Holding the Detector:

Thread your arm through the armrest and strap.

Grasp the handle of the detector and rest your

forearm in the armrest.

Adjusting the Position of the Handle:

Your elbow should sit just above the back of the

armrest allowing you to comfortably grip the handle.

Slide the handle into position. Using a screwdriver,

tighten the two screws which hold the handle

onto the shaft. Adjust the handle strap to a

comfortable position.

Adjusting the Length of the Lower Shaft:

If the coil is too far from your body it will be difficult

to balance and manoeuvre while detecting.

If the coil is too close to your body it may detect your

pick, the battery, or any other metal which you are

carrying; causing confusing sounds.

Rotate the twistlocks of the shafts counter-clockwise

to ensure that they are loosened.

Compress the spring pins of the shafts and move

them up or down to suit. Once all shafts are clipped

into position, rotate twistlocks clockwise onto the

shafts until they are firmly clamped.

The correct length of the lower shaft should allow

you to swing the coil in front of your body without

any uncomfortable stretching or stooping.

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Tip: Some operators may

find it more comfortable

to fit the battery around

the waist. However, make

sure the GPX-4500 isn't

detecting a signal from the

battery. If using a large coil,

position the battery as high

up on your back as practical

(and comfortable) to avoid

any unwanted interference.

The aluminium battery case contains the 7.4V

Lithium Ion (Li-Ion) battery pack and an internal

charging circuit. Supplied with the GPX-4500 is

a mains charger adaptor and a 12V vehicle

charger adaptor.

When fully charged, the battery will provide

enough power to operate the detector for

approximately 12 hours.

The charger will recharge a flat battery in

approximately 5 hours, but partially discharged

batteries require a shorter recharge time. There is

no need to fully discharge the Li-Ion battery before

recharging, it can be recharged at any time you are

not detecting.

Note: Some after market coils can drain the battery at

a higher rate which may reduce your operating time

by up to 30%.

Mains Charger Adaptor

The mains charger adaptor will charge the battery

from local mains (AC) power outlets.

To Charge with the Mains Charger Adaptor:

1 Disconnect the power cable from the battery.

2 Connect the mains charger adaptor to the

battery power plug and the wall socket.

3 Switch the wall socket on.

Vehicle Charger Adaptor

The vehicle charger adaptor will charge the

battery from the accessories socket (cigarette

lighter) of most motor vehicles. The socket must

be 12–24VDC.

To Charge with the Vehicle Charger Adaptor:

1 Disconnect the power cable from the battery.

2 Connect the vehicle charger adaptor to the

battery and to the vehicle accessories socket.

The colour scheme of the tri-colour LED (pg. 20)

will indicate the status of the charging process.

Note: Don't leave the battery on charge in a closed

vehicle on a hot day as it is temperature protected

and will stop charging.

Charging the Battery

Tip: A spare battery is

available as an accessory. If

travelling into remote areas

a spare battery will ensure

you can continue detecting

for long periods of time.

To prevent damage to the battery, do not

start the vehicle's engine while the battery

is connected.

Make sure your vehicle's battery is in good

condition before using it to charge the

GPX-4500 battery.

The colour scheme of the tri-colour LED (pg. 20) will

indicate the status of the charging process.

Caution: The battery should initially be charged

for 8 hours before use.

The Lithium Ion battery is specifically designed

for the GPX-4500.

The Lithium Ion battery is not compatible with

non GPX detectors. The GPX-4500 is supplied with a

power lead which has been specifically designed to fit

GPX detectors only. Attempting to use the Lithium Ion battery

pack with other detectors may damage the detector or the battery pack.

Do not try to adapt this battery to other models as it will very likely

cause damage.

• Do not charge the battery at temperatures above 45°C (113°F).

• Do not charge the battery at temperatures below 0°C (32°F).

• Do not leave the battery in hot conditions (e.g. on the dashboard

of your car or rear parcel shelf).

• Do not immerse the battery in any liquid or allow water ingress.

• Do not throw the battery or impact it in any way.

• Do not short-circuit the battery.

• Do not use the battery if it is damaged or deformed.

• Do not disassemble or reconstruct the battery.

• Do not incinerate the battery.

In the event of a fault, you should return the battery to a Minelab

authorised service centre for repair.

The use of non-approved components will VOID YOUR WARRANTY.

There are no user serviceable parts within this battery pack.

Battery LED Patterns

Brief cycling red-orange-green: Occurs when the charger is turned on or when

a new battery is connected

Solid orange: First phase of charge

Orange with green blink: Last phase of charge

Solid green: Battery is charged

Slow red blinking: The battery is too hot. It has reached a

temperature over 50°C (122°F) and will not

charge. Disconnect the battery and wait for

it to cool below 40°C (104°F) in a cool place

before reconnecting.

Continuous orange blinking: The first phase of charging has timed out. If

this continues to occur each time the battery

is charged the battery is no longer functioning

correctly. Contact your dealer.

Solid red: There is a fault with the battery.

Disconnect and reconnect the battery.

If the LED is still red contact your dealer.

Routine

Exceptions

Taking Care

of Your Battery

Detector Sounds

Target Response

(Metal Object Response)

This is a change in the tone (pitch)

and volume of the Threshold

when a target is detected and not

discriminated (rejected).

Threshold (Background sound)

This is the background sound produced

by the detector. When a target is

detected, the Threshold (pg. 34)

changes in volume and pitch. Listen to

the Threshold carefully. Concentration

is an important part of detecting.

A very deep or small target may only

cause a very small change to

the Threshold.

Electrical Interference

The detector may produce random

sounds when the coil is motionless.

These will not be target signals, but

signals caused from the surrounding

environment. The GPX-4500 has a Tune

(pg. 32) function to overcome electrical

interference.

Note: The GPX-4500 is a

‘motion’ detector. This

means it must be moving

over a target to detect it.

Detecting Basics

The GPX-4500 will perform at its best when the coil

is kept close and parallel to the ground at all times.

This will increase the detection depth and target

response to small objects.

A variation in coil height at the end of each swing

may cause confusing sounds and reduce detection

depth; an even flat sweep is desirable.

Practise sweeping the coil over the ground in a

side-to-side motion, while walking forward slowly at

the end of each sweep. Slightly overlap the previous

sweep to ensure full ground coverage. An average

sweep speed is four seconds from left to right to left.

Ground Noise

Certain minerals may cause the

detector to produce various sounds;

often referred to as false signals. The

GPX-4500 has an automatic Ground

Balance function (pg. 38) to overcome

ground noise.

Blanking

When the detector is in Iron Reject

mode and sweeping over a ferrous

target the Threshold ‘blanks’ (becomes

silent), indicating that a target is

located underneath the coil but has

been rejected. Blanking (pg. 79) is a

useful way of distinguishing between

desired and undesired targets.

Low Battery

When the battery voltage (pg. 55) is

low, a series of alarm signal pulses are

given at one minute intervals.

Tip: When using a Monoloop coil more overlap is

required to ensure that targets at maximum depth are

not overlooked (see pg. 90 for a diagram showing coil

search patterns).

Auto Tune

Mode

Soil /

Timings

Ground

Balance

Coil /

CancelTrackingSpecialDeep

Custom Enhance Fixed Double D

MNG

Threshold

Coil

Smart

Point

Search Mode

(pg. 28) Each Mode

has factory preset

settings to suit that

style of searching.

Search Modes can

also be customised

to suit different

detecting conditions.

Soil/Timings

(pg. 36) allows

you to change the

electronic pulses/

timings of the

detector to optimise

performance for

different soils and

target types.

Ground Balance

(pg. 38) reduces

the ground

noise caused by

mineralisation.

Coil/Rx (pg. 44)

allows you to

change the

transmit and

receive (Rx) fields

of the coil.

Auto Tune (pg. 33) automatically scans

a range of frequency channels to help

reduce electrical interference.

Coil Connector

Connects the coil to the control box.

Smart Point is a connection point

for the Quick-Trak button located on

the handle.

Threshold (pg. 34) is the background

sound produced by the detector. This

control increases / decreases the level

of the Threshold.

Front Control Panel Rear Control Panel

Function

Select

Setting

On/Off

Hold for FP

Setting (pg. 51)

Once a function

has been selected,

Setting allows you to

adjust its value.

Function Select

(pg. 50) scrolls up or

down through the list

of functions.

LCD

(Liquid Crystal Display)

Displays all the menu

functions and settings.

Now with backlight

(pg. 54).

Battery Connector

connects the control

box to the battery

and headphones.

On / Off (pg. 26)

turns the detector

on and allows you

to restore Factory

Presets.

Turning the Detector On

Function

Select

Setting

On/Off

Hold for FP

It is best to only turn the detector on

when outdoors and away from sources

of electromagnetic disturbance such

as power lines, transmitters, electric

fences and phone towers. These

sources may cause the detector to

perform erratically, giving numerous

false signals.

Note: If the detector emits an overload

sound move the coil away from any

large metal objects. Overloading is

not harmful to the electronics of

the detector.

The On / Off switch is located

on the rear control panel.

To turn the detector on or off:

Press and release the On / Off toggle switch.

Many of the GPX-4500

functions are accessed

through the LCD Menu.

These are explained in

further detail throughout

the rest of this manual.

Until you become more

familiar with the GPX-

4500, the detector can

simply be operated with

the Factory Presets

(pg. 48) and the front

panel controls.

Functions Settings

LCD Menu Structure

Avoid turning the detector on and off repeatedly.

If this happens the Coil Overcurrent screen will

appear. Turn the detector off and wait for a short

time before turning the detector on again.

Search Mode

The GPX-4500 has three Search Mode switch

positions: General, Deep and Custom.

Each Search Mode switch position has a series of

Factory Preset settings saved so that you can start

detecting right away. After you are familiar with the

GPX-4500 these can be customised with personal

preferences to suit different detecting conditions.

The General and Deep modes have their own switch

position. Custom Mode position is for one of the

four additional search modes (pg. 64), which you can

select through the LCD menu.

General (G)

The General Mode will provide the best compromise

of sensitivity, stability, depth and signal response

under a variety of conditions. For this reason it is

likely that General will be your primary search mode,

reserving the others for a specific task or scenario.

Deep

The Deep Mode should be used when you are

detecting a small area very slowly and carefully; such

as when chaining or cross-gridding a run of nuggets

on a slope. Deep Mode is optimised for a very slow

sweep to provide maximum depth, on large targets.

Auto Tune

Mode

Soil /

Timings

Ground

Balance

Coil /

CancelTrackingSpecialDeep

Custom Enhance Fixed Double D

MNG

Threshold

Coil

Smart

Point

Custom

The Custom Search Mode provides a choice of four

additional search modes (pg. 64) which can be

selected from the LCD menu.

These are: – Patch (Factory Preset Selection)

– Hi-Mineral

– Hi-Trash

– Test A

This allows a total of six separate search modes

which can be set up for different circumstances.

The Main Menu

functions are the

same for each

Search Mode.

The functions for

each of the six

Search Modes

can be saved with

different settings.

Auto Tune

Mode

Soil /

Timings

Ground

Balance

Coil /

CancelTrackingSpecialDeep

Custom Enhance Fixed Double D

MNG

Threshold

Coil

Smart

Point

Auto Tune

Mode

Soil /

Timings

Ground

Balance

Coil /

CancelTrackingSpecialDeep

Custom Enhance Fixed Double D

MNG

Threshold

Coil

Smart

Point

Auto Tune

Mode

Soil /

Timings

Ground

Balance

Coil /

CancelTrackingSpecialDeep

Custom Enhance Fixed Double D

MNG

Threshold

Coil

Smart

Point

Auto Tune

Mode

Soil /

Timings

Ground

Balance

Coil /

CancelTrackingSpecialDeep

Custom Enhance Fixed Double D

MNG

Threshold

Coil

Smart

Point

Auto Tune

Mode

Soil /

Timings

Ground

Balance

Coil /

CancelTrackingSpecialDeep

Custom Enhance Fixed Double D

MNG

Threshold

Coil

Smart

Point

Auto Tune

Mode

Soil /

Timings

Ground

Balance

Coil /

CancelTrackingSpecialDeep

Custom Enhance Fixed Double D

MNG

Threshold

Coil

Smart

Point

Auto Tune

Mode

Soil /

Timings

Ground

Balance

Coil /

CancelTrackingSpecialDeep

Custom Enhance Fixed Double D

MNG

Threshold

Coil

Smart

Point

Auto Tune

Mode

Soil /

Timings

Ground

Balance

Coil /

CancelTrackingSpecialDeep

Custom Enhance Fixed Double D

MNG

Threshold

Coil

Smart

Point

Auto Tune

Mode

Soil /

Timings

Ground

Balance

Coil /

CancelTrackingSpecialDeep

Custom Enhance Fixed Double D

MNG

Threshold

Coil

Smart

Point

Search Mode

(Continued)

Selecting Custom Mode

When the Search Mode switch is in the Custom

position each of the four Custom Search Modes

(pg. 64) are available, and can be selected from the

LCD menu.

The four Custom Search Modes are:

Custom Search Mode - Patch

The Patch mode is set up for prospecting unknown

ground when you are likely to be walking and

detecting faster, seeking a first nugget that may

indicate a new area worthy of further investigation.

Custom Search Mode - Hi Mineral

This mode will help to stabilise the detector in highly

mineralised soils, yet still remain sensitive to small

and deep targets. You may need to adjust the Rx

Gain setting to suit your particular location.

Custom Search Mode - Hi Trash

This mode has factory presets specifically selected

for detecting in an area containing a lot of rubbish.

The Iron Reject (pg. 78-81) setting has been factory

set quite high so you may want to reduce this if you

want to be more cautious.

Custom Search Mode - Test A

This is a default mode initially set with the same

settings as General, which you can use to experiment

with and compare with other modes.

All four of these Custom Search Modes can be

renamed (pg. 82).

Note: Tuning should be

done initially with the

Coil switch in Double-D

or in Monoloop (M). If the

interference is still severe

after completing the tuning

operation change the Coil

switch to Cancel and then

re-tune the detector if

necessary.

Tune

Reducing Electrical Interference

To Perform an Automatic Tune:

1 Hold the detector at waist height, with the coil

vertical, and slowly rotate through a half-circle.

Make sure there are no large targets or obvious

electrical interference sources close by.

2 Face the direction of the most interference and

hold the coil steady.

If you have difficulty holding the detector very still

for 60 seconds, you can place the detector on the

ground with the coil vertical.

3 Press the Auto Tune button. Keep the detector

completely still during the automatic channel

scanning process.

A single beep indicates the beginning of the Auto

Tune. The detector will begin to scan each channel

for the least interference. This may take up to

60 seconds.

The detector will select the quietest operating

channel identified. The end of the Tuning process

will be indicated by three sharp ‘beeps’.

When tuning the detector in close proximity to other

detectors, each operator needs to take turns tuning.

Do not try to tune two detectors at the same time.

Any interference is made more obvious with a faster

Motion setting (pg. 66). Therefore, you can assist

the Auto Tune function in selecting the quietest

frequency band by selecting Fast Motion before

performing the Auto Tune process. When the process

is complete simply return the Motion speed to its

original setting.

The detector may be affected by electrical

interference from powerlines, radio transmitters

electrical equipment or other detectors operating

close by. This interference causes the Threshold to

become erratic.

So that the detector experiences the least

interference for the current environment the search

channel can be changed automatically by the Auto

Tune button on the control panel, or manually in the

Manual Tune (pg. 63) setting via the LCD menu.

Auto Tune instructs the detector to automatically

listen to every channel and select the quietest

position. Automatic tuning may take up to 60

seconds.

The Manual Tune setting, via the LCD menu, allows

you to manually select and listen to every channel

for the least interference.

The best channel to select will be the one where the

audio response to electromagnetic disturbances

(e.g. powerlines) is the lowest.

It is best to tune with the coil away from the

ground and as stationary as possible. This gives the

detector the best chance of sensing all surrounding

interference (not associated with the ground or

targets) too select the quietest channel.

Note: Interference in some locations can change

during the course of the day so you may need to re-

tune from time to time to maintain a stable Threshold

as you move around the area.

There is only one Tune setting. Any changes made

manually will override the Auto selection.

Auto Tune

Tip: If you would like to

know what channel has

been chosen after an

automatic Tune, access

the Manual Tune screen

and check the number

displayed.

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Threshold

Adjusting the Background

Audio Level

Threshold is the constant audible background tone

or 'hum' produced by the detector. The Threshold

is your reference point and lets you know what the

coil is picking up, whether it may be a target, ground

noise, or electrical interference, so it is important to

set the threshold so it can be heard.

The level of the Threshold should be set low, but still

audible and stable. Ideally it should be a smooth,

gentle hum. If you set it so that it can't be heard you

may set other detector settings incorrectly.

Small targets or large deep targets may not produce

a distinct target signal, but may cause only a small

variation in the Threshold. If the Threshold level is

set too high or too low these very small variations

may be missed.

Listening for a target signal with a high Threshold

would be like trying to hear a whisper within a

crowded noisy room. A high Threshold may also be

uncomfortable to your hearing.

If the Threshold is set too low the target signal needs

to be loud enough to become audible. Therefore,

very soft target signals, from small or very deep

targets, may not be heard.

It is important to reset the Threshold level as

conditions change. For example, your ears may

adjust to the low levels of audio after an hour or so,

or the conditions may have become windy.

Threshold

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When the Threshold

is too high a faint signal

is masked and only the

peak of the loud signal

is audible above

the Threshold.

With the Threshold set

correctly both target

signals are easily heard.

A Threshold level that

is too low does not allow

faint target signals to

be heard.

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Minelab GPX-4500 User manual

Brand: Minelab

Model: GPX-4500

Category: Measuring, testing & control

Type: User manual

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Minelab GPX-4500 User manual

Minelab GPX-4500 User manual

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